1. Field of the Invention
The present invention relates to an absorption type refrigeration apparatus and particularly to an absorption type refrigerating apparatus which has a function of removing noncondensible hydrogen gas generated during the absorption refrigerating cycle operation with reducing reaction.
2. Description of the Related Art
Absorption type refrigerating apparatuses have been known for use as cooling apparatuses which are operated in an absorption refrigerating cycle. Also, as their advantage over the efficiency of energy utilization during the operation is focused, absorption type refrigerating apparatuses are increasingly demanded for carrying out a heat pump warming operation with the use of heat pumped up by an evaporator from the ambient atmosphere in addition to the cooling operation. For example, disclosed in Japanese Patent Publication (Heisei) 6-97127 is an absorption type hot/cool water supplier capable of conducting three different modes of operation; cooling, warming by heat pump action, and warming by direct burner (boiler) heating.
In the absorption refrigerating cycle of such an absorption type refrigerating apparatus, contact reaction between the contents of a refrigerant, the metal material of refrigerant conduits, and an anti-corrosion agent may generate a small amount of noncondensible gas such as hydrogen. It is said that the existence of noncondensible gas unfavorably affects the vacuum condition of the absorber or evaporator which should be maintained at as low a pressure within the range from a few mmHg to a few hundreds mmHg and thus declines the operational efficiency of the cooling and warming action. This requires an extracting means, such as a vacuum pump, for periodically carrying out a maintenance operation to discharge the noncondensible gas to the outside.
Such apparatuses for discharging the noncondensible gas from an absorption type refrigerating apparatus to the outside are disclosed in Japanese Patent Laid-open Publications (Heisei) 8-121911 and (Heisci) 5-9001. Those apparatuses allow the noncondensible gas to be separated from a refrigerant liquid and transferred into a heated palladium conduit where it is discharged to the outside by the action of selective permeability of palladium.
In an absorption type refrigerating apparatus employing an alcohol refrigerant medium, such as fluoride alcohol for operating the absorption refrigerating cycle, the refrigerant medium is mixed with water for inhibiting corrosion of the metal material of a refrigerant conduit. This, however, causes the water to react with aluminum in the refrigerant conduit material thus generating a small amount of hydrogen gas which has then to be removed.
The generation of hydrogen gas derives from the following anode and cathode reactions. The anode reaction is expressed by A1xe2x86x92A13+3e and A13+OHxe2x86x92A1OOHxc2x7H2O (hydration of aluminum ions or deposition of a boehmite layer) and the cathode reaction is expressed by 3H+3exe2x86x923/2H2 (generation of hydrogen).
When the refrigerant medium is not of an alcohol type but is water in combination with an absorbent of lithium bromide (LiBr) or is ammonia (NH3) in combination with an absorbent of water, hydrogen gas is released and has to be removed.
The noncondensible gas discharging apparatuses disclosed in the above publications have the following drawbacks. As the noncondensible gas discharging apparatuses are designed for discharging hydrogen gas to the outside, their constructions are too complex to maintain air-tightness. Also, as water in the refrigerant medium is reduced gradually, its amount required for inhibiting the corrosion can hardly be maintained.
It is an object of the present invention, in view of eliminating the above drawbacks, to provide an absorption type refrigerating apparatus capable of discharging noncondensible gas while maintaining a desired amount of water contained in the refrigerant medium without reducing the level of vacuum in the apparatus.
An example of the present invention having the first feature of this invention comprises an evaporator in which a refrigerant is stored, an absorber for absorbing a refrigerant vapor generated in the evaporator with the use of an absorbent solution, a regenerator for heating up the absorbent solution to extract the refrigerant vapor and thus recover concentration of the absorbent in the solution, and a condenser for condensing the refrigerant vapor extracted in the regenerator before transferring back the same to the evaporator, wherein the condenser has a reduction unit provided in the interior thereof for holding fundamentally a metal oxide which oxidizes hydrogen gas to water, which hydrogen gas being produced during the absorption refrigerating cycle operation.
An example of the present invention having the second feature of this invention is constructed so that the temperature of the reduction unit is maintained close to, or at least not lower than, the condensation temperature of the refrigerant.
An example of the present invention having the third feature of this invention is constructed so that the reduction unit is accommodated in a chamber of which the outer wall is of the condenser and which is fluidly communicated with the condenser for maintaining the temperature of the reduction unit close to the condensation temperature of the refrigerant.
According to these features of the present invention, the hydrogen gas acts on the oxidizing metal and is turned to water due to the reducing reaction or deoxidization of the oxidizing metal and can thus be eliminated. This inhibits the operational efficiency from being reduced with decreasing of the vacuum condition of the condenser, the evaporator, the absorber, and the refrigerant medium conduits. More particularly, water generated by the reduction is transferred to the refrigerant medium conduit, hence allowing the refrigerant medium to maintain its water content to a desired amount. As the reduction unit is mounted in the condenser, it can favorably draw heat needed for the reducing reaction from the refrigerant vapor.
In particular, as the reduction unit is provided in the condenser, its reducing reaction can be further promoted by the heat of the refrigerant vapor.